相关论文: Study of $B_s\to \phi \ell^+ \ell^-$ decays in the…

We present the first unquenched lattice-QCD calculation of the form factors for the decay $B\rightarrow D^\ast\ell\nu$ at nonzero recoil. Our analysis includes 15 MILC ensembles with $N_f=2+1$ flavors of asqtad sea quarks, with a strange…

We study the hadronic matrix elements describing the $B_s \to D_s\ell \bar\nu_\ell$ decay in and beyond the Standard Model. By using the twisted mass QCD on the lattice with $N_f=2$ dynamical flavors we compute the normalization $\mathscr…

The branching fractions of the rare weak $B\to \pi l^+l^-(\nu\bar\nu)$ and $B\to\rho l^+l^-(\nu\bar\nu)$ decays are calculated in the framework of the relativistic quark model based on the quasipotential approach. The form factors…

We investigate the decays $B_c^- \rightarrow D_{s}^{(*)-}\ell^+\ell^-$ and $B_c^- \rightarrow D_{s}^{(*)-}\nu\bar{\nu}$ within the Standard Model (SM), employing perturbative QCD form factors that are sensitive to the wave functions of…

We present HPQCD's improved scalar, vector and tensor form factors for $B \to K$ semileptonic decays, using the heavy-HISQ formalism for more accurate normalisation of the weak currents. Working with masses close to the physical $b$ on the…

We calculate semileptonic form factors for the decays $B_c \to \eta_c \, l \nu$ and $B_c \to J/\psi \, l \nu$ over the entire $q^2$ range, using a highly improved lattice quark action for charm at several lattice spacings down to $a=0.045$…

Motivated by recent anomalies in FCNC $b\to s\ell^+\ell^-$, we study $B_1\to B_2\ell^+\ell^-(\ell=e,\mu,\tau)$ semi-leptonic weak decays with the SU(3) flavor symmetry, where $B_{1,2}$ are the spin-1/2 baryons of single bottomed…

We study the semileptonic decays of $\Xi^{(')}_{b}\rightarrow\Xi^{(')}_{c}{\ell}\bar\nu_{\ell}$ in all lepton channels. To do this, we first obtain the form factors defining these decay modes within the framework of QCD sum rules. Then,…

We present results for semi-leptonic form-factors obtained on a statistical sample of $66$ $32^3 \times 64$ lattices at $\beta = 6.0$ using quenched Wilson fermions. We find $f_+^{D \to K l \nu}(q^2 = 0) = 0.73 \pm 0.06$, $A_2/A_1({D \to…

We analyze the semileptonic (B_c -> B_u* l+ l-) decay in the frame work of the Standard Model. We calculate the (B_c) to (B_u*) transition form factors in QCD sum rules. Analytical expressions for the spectral densities and gluon…

Discrepancies have been noted between experimental measurements and Standard Model predictions for various observables related to the $B\to(K, K^*,\phi) ll$ processes. Recently, the Belle-II Collaboration observed a $2.8\sigma$ deviation…

In this work, we calculate the transition form factors for the weak decays $\Lambda_b^0 \to \Lambda_c(2860)^+$ and $\Lambda_b^0 \to \Lambda_c(2625)^+$ using QCD light-cone sum rules, and compute the branching fractions of the corresponding…

We compute the $B\to\pi\ell\nu$ semileptonic form factors and update the determination of the CKM matrix element $|V_{ub}|$. We use the MILC asqtad ensembles with $N_f=2+1$ sea quarks at four different lattice spacings in the range $a…

We present a study of semi-leptonic $\bar B\tp D\ell\bar\nu$ decays in quenched lattice QCD through a calculation of the matrix element $\la D|\bar c\gamma_\mu b|\bar B\ra$ on a $24^3\times 48$ lattice at $\beta=6.2$, using an…

We calculate the form factors for the semileptonic decays $B_s\to K\ell\nu$ and $B\to K\ell\ell$ with lattice QCD. We work at several lattice spacings and a range of light quark masses, using the MILC 2+1-flavor asqtad ensembles. We use the…

We calculate the transition form factors of the semileptonic $B_c\rightarrow \chi_{c2} l \bar{\nu} $ in the framework of QCD sum rules taking into account the two-gluon condensate corrections. Using the obtained results of form factors we…

The semileptonic $B_s (B) \to K_2^*(a_2, f_2) \ell\nu$, $\ell=\tau, \mu$ transitions are investigated in the frame work of the three-point QCD sum rules. Considering the quark condensate contributions, the relevant form factors of these…

We have computed the form factors for B --> pi and D --> K(pi) semileptonic decays on the lattice by using full non-perturbative O(a) improvement, in the quenched approximation. Our results are expressed in terms of few parameters which…

We perform the first lattice calculation on the semileptonic decay of $J/\psi$ using the (2+1)-flavor Wilson-clover gauge ensembles generated by CLQCD collaboration. Three gauge ensembles with different lattice spacings, from 0.0519 fm to…

Semileptonic B meson decays induced by $b \to s(d) l^+ l^-$ flavour changing neutral current (FCNC) transitions are very important to probe the quark-flavour sector of the standard model (SM) and also offer a probe to test new physics (NP).…